There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

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Principles Of Optics Electromagnetic Theory Of Propagation Interference And Diffraction Of Light

Ultra-wide Band (UWB) technology is a new, useful and safe technology in the fleld of wireless body networks. This paper focuses on the feasibility of estimating vital signs | speciflcally breathing rate and heartbeat frequency | from the spectrum of recorded waveforms, using an impulse-radio (IR) UWB radar. To this end, an analytical model is developed to perform and interpret the spectral analysis. Both the harmonics and the intermodulation between respiration and heart signals are addressed. Simulations have been performed to demonstrate how they afiect the detection of vital signs and also to analyze the in∞uence of the pulse waveform. A fllter to cancel out breathing harmonics is also proposed to improve heart rate detection. The results of the experiments are presented under difierent scenarios which demonstrate the accuracy of the proposed technique for determining respiration and heartbeat rates. It has been shown that an IR-UWB radar can meet the requirements of typical biomedical applications such as non-invasive heart and respiration rate monitoring.

/pdf/analysis-of-vital-signs-monitoring-using-an-ir-uwb-radar-3dvli0yol5.pdf

Analysis of vital signs monitoring using an ir-uwb radar

Ultrawideband (UWB) radar technology has emerged as one of the preferred choices for through-wall detection due to its high range resolution and good penetration. The resolution is a result of high bandwidth of UWB radar and helpful for better separation of multiple targets in complex environment. Detection of human targets through a wall is interesting in many applications. One significant characteristic of human is the periodic motion, such as breathing and limb movement. In this letter, we apply the UWB radar system in through-wall human detection and present the methods based on fast Fourier transform and S transform to detect and identify the human's life characteristic. In particular, we can extract the center frequencies of life signals and locate the position of human targets from experimental data with high accuracy. Compared with other research studies in through-wall detection, this letter is concentrated in the processing and identifying of the life signal under strong clutter. It has a high signal-to-noise ratio and simpler to implement in complex environment detection. We can use the method to search and locate the survivor trapped under the building debris during earthquake, explosion, or fire.

Through-Wall Detection of Human Being's Movement by UWB Radar

We focus on predicting sleep stages from radio measurements without any attached sensors on subjects. We introduce a new predictive model that combines convolutional and recurrent neural networks to extract sleep-specific subject-invariant features from RF signals and capture the temporal progression of sleep. A key innovation underlying our approach is a modified adversarial training regime that discards extraneous information specific to individuals or measurement conditions, while retaining all information relevant to the predictive task. We analyze our game theoretic setup and empirically demonstrate that our model achieves significant improvements over state-of-the-art solutions.

/pdf/learning-sleep-stages-from-radio-signals-a-conditional-50xelkslt0.pdf

Learning sleep stages from radio signals: a conditional adversarial architecture

Holographic subsurface radars (HSR) are not in common usage now; possibly because of the historical view amongst radar practitioners that high attenuation of electromagnetic waves in most media of interest will not allow sufficient depth of penetration. It is true that the fundamental physics of HSR prevent the possibility to change receiver amplification with time (i.e., depth) to adapt to lossy media (as is possible with impulse subsurface radar or ISR). However, use of HSR for surveying of shallow subsurface objects, defects, or inhomogeneities is an increasingly proven area of application. In this case, HSR can record images with higher resolution than is possible for ISR images. The RASCAN family of holographic radars is presented along with technical specifications and typical case histories. Among the applications considered are civil and historic building surveys, nondestructive testing of dielectric materials, security applications, and humanitarian demining. Each application area is illustrated by relevant data acquired in laboratory experiments or field tests. This paper presents experiments with RASCAN imaging in media with different degrees of attenuation, and illustrates the principle of HSR through an optical analogy.

Holographic Subsurface Radar of RASCAN Type: Development and Applications

The radar capable to detect and perform diagnostics of a state of the human being behind obstacles and in conditions of bad visibility could be used for the manifold applications. The potential consumers of the radar are: rescue services, antiterrorist detachments and law-enforcement bodies. It is possible also to use this device in medicine. In this paper, the experiments with using of continuouswave subsurface radar are described. The recorded oscillograms and their frequency spectrums for heartbeat, respiration and articulation of a man, which is taking place behind an obstacle (wall), are presented.

/pdf/detection-of-human-breathing-and-heartbeat-by-remote-radar-1efh4r5qmj.pdf

Detection of Human Breathing and Heartbeat by Remote Radar

A radar for detecting and testing health condition of an individual, who is separated from the radar by a non-metal wall or in poor visibility, could be useful in many critical services such as medicine, rescue service, law and antiterrorists enforcements In this paper, we describe the theoretical approach and experiments utilizing a continuous-wave subsurface radar. New theoretical results, experimental records and their frequency spectrums for heartbeat, respiration and articulation of a man are presented.

Through wall sensing of human breathing and heart beating by monochromatic radar

Methods of extracting information from observations of human subjects by short-range radars with various types of probing signals are theoretically analyzed. The time and frequency features of breathing and heartbeat realizations obtained by different demodulation methods from monochromatic and video-pulse probing signals are considered. Algorithms for discrimination of signals reflected by human objects from interfering reflections from local objects are modeled for continuous probing signals with stepwise frequency modulation.

/pdf/radar-methods-of-detection-of-human-breathing-and-heartbeat-50xm7c865f.pdf

Radar Methods of Detection of Human Breathing and Heartbeat

The paper summarizes results of step-frequency radars application in medicine. Remote and non-contact control of physiological parameters with modern bioradars provides a wide range of possibilities for non-contact remote monitoring of a human psycho-emotional state and physiological condition. The paper provides information about technical characteristics of bioradars designed at Bauman Moscow State Technical University and experiments using them. Results of verification experiment showed that bioradars of BioRASCAN type may be used for simultaneous remote measurements of breathing and heart rate parameters. In addition, bioradar assisted experiments for detecting of different sleep disorders are described. Their results proved that method of bioradiolocation allows correct estimation of obstructive sleep apnea severity compared to the polysomnography method, which satisfies standard medical recommendations.

Sergey Ivashov

Papers

Holographic Subsurface Radar of RASCAN Type: Development and Applications

Detection of Human Breathing and Heartbeat by Remote Radar

Through wall sensing of human breathing and heart beating by monochromatic radar

Radar Methods of Detection of Human Breathing and Heartbeat

Application of step-frequency radars in medicine